Keep under wraps Informal

To keep something secret or hidden from public knowledge, especially a plan, project, or piece of information not yet ready to be revealed.

It’s frequently used about deliberately withheld announcements — a product, a decision, an event — kept concealed until an intended, more advantageous moment.

The phrase comes from horse racing, where jockeys wrapped the reins tightly around their hands to physically restrain a horse from running at full speed — either to conserve the horse’s energy for a final sprint or to deliberately conceal its true racing ability from spectators and competitors before an important race. The trade publication “The Blood Horse” documented this literal racing sense in its March 11, 1955 issue, describing a rider who had “wrapped his reins around his hands in order to obtain sufficient purchase on the leader to restrain the horse from full speed.” The figurative sense of concealing anything, not just a horse’s ability, spread from racing into broader sports usage in the early 20th century before settling into today’s fully general meaning.

The company kept the new product under wraps until launch day.

Details of the wedding were kept under wraps.

They kept the merger under wraps for months.

A: “What’s the surprise?” B: “It’s staying under wraps for now.”